Surface active compounds and method for the production thereof



SURFACE ACTIVE COMPOUNDS AND METHOD FOR THE PRODUCTION THEREOFWillehrord Jean Francois de-Riik V. D. Gracht,'-Baasrode, Belgium,assignor to Lever Brothers Company, New York, N. Y.,a*corporationofrMaine No Drawing. Application April'7, 1952, Serial .No. 281,031

Claimspriority,"appiication Netherlands April 10, :1951

7 Claims. (CI. 99-23) This invention relatesto-novel surface activecompounds and-to a method for their production.

The novel compounds of this invention have llllllty in the preparationofemulsions'and may beemployedxto prepare or stabilize'such emulsions asmargarine,baking plate greasersointmen'ts, hair drcssings'andfacecreams.

The novel compounds-of'tliis invention are'also suitable for preparingwater-in-oil emulsions containing as much as 80%Water.

The novel compounds of this invention :also have utility as additivesfor liquid chocolate and particularly chocolateused in the formation ofchocolate coatings for ice cream briquettes which contain water,Whencoating ice cream briquettes with chocolate, pieces .of ice creamflake off of the briquette and'become mixed with the coating. The waterfrom such flaked off pieces .causes the finely ground sugarparticles inthe sugar coating to agglomerate, resulting in a thickening of thecoating. This, in .turn, makes the coating diflicult to spread .dutingthe coating operation. With a coating containing the novel compoundsofthis invention, any Water from-pieces of ice cream entering thecoating .is emulsifiedin'thefat of the coating as a result of theinherent action of .the novel compounds in promoting the formationcofWaterin-oil emulsions. This prevents the Water from contacting the sugarparticles 'to any great extent .so/that .any undue thickening of thecoating due .to water .fromlice cream flakes is prevented.

Generally speaking, the novel compounds are produced by reacting .apolycondensed 'hydroxyca'rboxylic acid having at least 8 carbon atomswith a ,polycondensed polyhydric alcoholhaving at 'least 3 carbon atoms.

Preferably the hydroxycarboxylic acid has .from .12 to 20 carbon atomsand an acid .number =not.in excess of70'and the polyhydric alcohol hasfrom 3 .to 6.carbon atoms.

The compounds obtained by polycondensation of 'hydroxycarboxylic acidsare known .as estolides. .The term polycondensation as .used hereinmeans.a reaction in which a number of molecules of the same compound combineto formjlargcr-molecules while water is eliminated. In order to obtaindesired products, it isnecessary thatthe.hydroxycarboxylicacidstbepolycondensed before esterification 'with a.polycondens-ed polyhyd-ric alcohol to form apartial.esterorpartial.estereether.

The hydroxycarboxylic acids which may -be .polycondensed may beany ofthe Yunsaturatedcr saturated-acids havingfrom 12'to 20 carbon atoms..Examplesofsuch acids are ricinoleieacid, monoor .dihydroxystearic acidsor mixtures thereof such as caster oilfattyacids dihydroxy acid obtained'fronrpalmitoleic acid,ttetrah.ydroxy acid obtained (from linoleic.acidandthe hexahydroxy acid obtained fromlinoleicacid or fromeleostearic acid. Further, synthetic hydroxy acids .such as .thoseproduced by the 0x0 process may beused.

The hydroxycarboxylic acids may .be ,polycondensed byheating underreduced pressure. Anzinert g-as-qsuchas nitrogen .or carbon dioxide maythen hepassed through Patent *6 2,785,978 Ratented Mar. 19, 1957 'ice"the acid while heating is continued. Oxidizing .gases 'shou'ld'not beused. The temperature :of polycondensa- 'tionof the hydroxycarboxylicacids depends upon the -natureof.the'fatty'acids. =Generally, thepolycondensation may'beperformed'at at temperature of from 200 to'.23 0"C.

for a period between 'about two and "about 15 'hours,

depending upon the degree "of condensation .desired.

Polycondensation of thehydroxycarboxylic acid should be performed so ato provide anacid number preferably :between.25;and 70in. the finishsdproduct. .For example,

.ricinoleic .acid, which gives good results when used in the process ofthis invention, may-=.be,-heated:in-vacuo for about,5 hours atatemperature between about 205 and :about 210 vC. The resulting,,polyricinoleic .acid :has "an acid number of 42. :If ztheheatingxiscontinued for 10 .hours, the acid number of the :polyricinoleic aciddrops to 35. Good emulsifying agents have been obtainedusingricinuleicaacidiestolides obtained by rpol-ycondensing the =estolidestuntil their acidanumber was ronly 25.

.Ihepolyhydric alcohols which may be employed are athosethaving from 3[i016 carbon atoms. Suitable polycondensates 'of gpolyhydric ,z'alcoholscontaining at least 3 .carbon atoms include .polyglycerols,polyerythritols, polypentaerythritols and .polymannitols. The.polycontdensation of the polyhydric alcohols :m'ay l'bc continued.h-ydric alcoholsma-ybe performedbyheatingthe alcohol in .vacuo atatemperature.betweeuabout 220 and about 250 .C. forlO .to.16lhours..Au-y Well-known esterifica- :tioncatalystmay .be used such as stannouschloride, zinc chloride, -zinc ,oxide, aluminum chloride, and magnesiumchloride.

Esterification is accomplished by heating the polycondensedhydroxycarboxylic acid and the polycondensed polyhydricsalcoholtogether. The reaction time .and temperature depend upon the nature of:the reaction components. A temperature in the range of 180m 230 C. hasbeen found 'to give goodresults. The reaction ;procee'cls below 180 C.but .at such temperatures tends to-be slow. ,The esteiificationreactionis continued until the reactionproduct hasadow .acidnumberwhich, generally speaking, means .below 10 and preferably below 1.5. "Itmay be desirable Fin some instances to conduct the reaction 'in vacuo..An inert gas .may also be passed through the reaction mixture.

Any catalystnormally employed vin esterification processes iforesterifying fatty .acids with alcohols may .be employed such as thosepreviously mentioned for use;in the polycondensation of the polyhydricalcohols.

The partial esters or ester-others prepared bythe process of itheinvention *have proved to be good emulsifying and stabilizing agents inwater-in-oil emulsions. 'The vaqueous solution.

The ;invention will be further illustrated by reference ztoithefollowing specific examp'lesz EXAMPLE 1 Preparationof.a.partiakpolyglyceroLester of polyricinoleic acid Aunixture iof fattyacids having an acidnumb'er of 170,

. of Example 1.

1 acid number dropped to 31.3. .then heated in vacuo to 180 C. with byweight of -the cases"(b)., (c) and (d).

perature between 200 and 210 C. in vacuo for 16 hourswhile nitrogen gaswas passed through the mixture. At

.the end of this period the acid number had dropped to 35; 100 parts byweight of the resulting estolides were then esterified with 10 parts byweight of polyglycerol (n =1.48O8) by heating the mixture in vacuo forfive hours at 210 C. while nitrogen gas was passed through the reactionmixture. The partial ester product had an acid number of 1.2 and anindex of refraction EXAMPLE 2 To illustrate the utility of the productof Example 1 an emulsion was prepared by mixing 72 parts by weight ofsunfiowerseed oil with 8 parts by weight of the product After heating to60 C., 320 parts by Weight of hot water were emulsified in the mixture.A fluid water-in-oil emulsion was obtained.

v The emulsion was very stable and did not break when compressed.

For comparison, an emulsion was prepared with an emulsifying agentobtained by esterifying noncondensed ricinoleic acid with 10% by weightof polyglycerol= (n =l.4812) at 210 C. The emulsion was poor andseparated completely into its competent parts.

A satisfactory emulsion was also prepared by mixing 38 parts by weightof sunfiowerseed oil, 60 parts by weight accordance with Example 1.

EXAMPLE 3 Preparation of partial esters of polyglycerol andpolycondensed monohydroxy stearic acid Monohydroxy stearic acid,obtained by splitting hydrogenated castor oil and having an acid numberof 185, was heated in vacuo at 140 C. for 14% hours while carby heatingfor 6 /2 hours at 210 C. while carbon dioxide gas was passed through thereaction mixture. ing product had an acid number of 2.

EXAMPLE 4 Preparation of partial esters of poiyglycerol andpolycondensed dihydroxy stearic acid Dihydroxystearic acid, prepared bythe alkaline per- The result- -manganate oxidation of crude tea-seed oilas described in Journal fiir praktische Chemie 33, p. 304 (1886), andhaving an acid number of 185, was polycondensed in vacuo at 200 C. Afterheating for 2 hours while carbon of water. and 2 parts by weight of theproduct prepared in- -bon dioxide gas was passed through the reactionmixture,v

dioxide gas was passed through the reaction mixture, the" The estolideproduct was polyglycerol (n =1.48l2) for 20 minutes while carbon dioxidegas was passed through the reaction mixture. .A thick fluid producthaving an acid number of 2 was obtained.

EXAMPLE 5 To illustrate the reduction in viscosity of chocolate coatingmixes for ice cream briquettes were prepared having 45% fat includingcocoa butter, 40% sugar, and

15% cocoa solids. Viscosity measurements were made at 38, C. on samplesof this coating containing (a) no emulsifier, (b) 0.3% lecithin,- (c)0.3% ofthe partial ester of Example 1, and (d) 0.15% of the partialester of Example 1. An average of 4 samples was made in each case andthe percentage lowering of viscosity calculated in The results obtainedwere,

(b) 0.3% lecithin, lowering of viscosity=23%, (c) 0.3%

of the partial ester of Example 1, lowering of viscosity:

43%, (d) 0.15% of the partial ester of Example 1, lower- EXAMPLE 6 Toillustrate the enhanced effect of the partial esters as produced inaccordance with Example 1 in preventing the thickening of chocolatecoatings for ice cream briquet tes due to pieces of ice cream becomingmixed with the coating, coatings containing (a) 0.3% lecithin, (b) 0.3%of the partial ester of Example 1, and (c) 0.15 of the partial ester ofExample 1 were used to coat ice cream briquettes. Samples of eachcoating were taken at the beginning and end of a days production ofbriquettes and the viscosity of these samples was measured. The resultsobtained were, (a) 0.3% lecithin, variation in viscosity during coatingoperation=+26%, (b) 0.3% of the partial ester of Example 1, variation ofviscosity during coating operation=5.5%, and (c) 0.15 of the partialester of Example 1, the variation in viscosity during coating operation:+11%.

Thus, it is apparent that the partial ester of Example 1 is considerablymore eifective than lecithin in preventing thickening of chocolatecoatings used for coating ice cream briquettes.

It will be obvious to those skilled in the art that many modificationsmay be made within the scope of the present invention without departingfrom the spirit thereof, and the present invention is to be restrictedonly in accordance with the appended claims.

I claim:

1. A method for the production of surface active agents which comprisesreacting an estolide of a substantially unpolymerized aliphatichydroxycarboxylic acid, having 12 to 20 carbon atoms and an acid numbernot in excess of 70, with a polycondensed polyhydric alcohol having 3 to6 carbon atoms at a temperature in the range of about 180 C. to about210 C. until the acid number drops to below 10.

2. A method for the production of surface active agents which comprisesreacting an estolide of a substantially unpolymerized aliphatichydroxycarboxylic acid, having 12 to 20 carbon atoms and an acid numbernot in excess of 70, with a polycondensed polyhydric alcohol having 3 to6 carbon atoms at esterification conditions until the acid number dropsto below 10.

3. The surface active agents produced by the process of claim 1.

' 4. A stabilized water-in-oil emulsion comprising a mixture of water,oil, and a minor quantity of a compound prepared by reacting an estolideof a substantially unpolymerized aliphatic hydroxycarboxylic acid,having 12 to 20 carbon atoms and an acid number not in excess of 70,with a polycondensed polyhydric alcohol having 3 to 6 carbon atoms at atemperature in the range of about 180 C. to about 210 C. until the acidnumber drops to below 10.

5. A fluid sugar-containing coating adapted for use on food productscontaining frozen water comprising a mixture of fat, sugar, and a minorquantity of a compound prepared by reacting an estolide of asubstantially unpolymerized aliphatic hydroxycarboxylic acid, having 12to 20 carbon atoms and an acid number not in excess of 70, with apolycondensed polyhydric alcohol having 3 to 6 carbon atoms at atemperature in the range of about 180 C. to about 210 C. until the acidnumber drops to below 10. 6. A fluid chocolate coating for food productscontaining frozen water comprising a mixture of cocoa butter, sugar,cocoa solids, 'and a minor quantity of a compound prepared by reactingan estolide of a substantially unpolymerized aliphatic hydroxycarboxylicacid, having 12 to 20 carbon atoms and an acid number not in excess of7O,

with-a polycondensed polyhydric alcohol having 3 to 6 References Citedin the file of this patent UNITED STATES PATENTS Priester May 2, 1939Ellis Nov. 12, 1940 Barth et a1 May 18, 1948 Schoenfeld Mar. 18, 1952

6. A FLUID CHOCOLATE COATING FOR FOOD PRODUCTS CONAININ FROZEN WATERCOMPRISING A MIXTURE OF COCOA BUTTER, SUGAR, COCOA SOLIDS, AND A MINORQUANTITY OF A COMPOUND PREPARED BY REACTING AN ESTOLIDE OF ASUBSTANTIALLY UNPLOYMERIZED ALIPHATIC HYDROXYCARBOXYLIC ACID, HAVING 12TO 20 CARBON ATOMS AND AN ACID NUMBER NOT IN EXCESS OF 70, WITH APOLYCONDENSED POLYHYDRIC ALCOHOL HAVING 3 TO 6 CARBON ATOMS AT ATEMPERATURE IN THE RANGE OF ABOUT 180* C. TO ABOUT 210*C. UNTIL THE ACIDNUMBER DROPS TO BELOW 10.